All entities need to register to do business (otherwise, the state can't get their tax revenue). The research for the original article, as well as all the research performed on this thread, has yet to come up with any official registration of Prometheus Methods Tower Services, Inc.. Was he running an under-the-table operation? Maybe. But that hardly makes the business "legitimate", nor does finding a reference on an obscure website.
The only semi-official validation that PMTS, Inc. exists is a credit report at Dun&Bradstreet. That could be the result of a good report... or a bad report (i.e. bills not paid).
What does all that mean? To me... it says that we are where we started. PMTS is either a two-bit one-man under-the-table operation that operated out of Penn, or it was registered as a foreign Corporation in an unknown land for revenues earned outside the country, or it didn't truly exist at all in the sense of a true business.
With respect to the convention at which Nick Berg had a booth... hanging a sign at a small convention does not make a legitimate business. If there was a big fancy website, it still proves nothing. It might help... as it did with hundreds of dot.com wonders that swindled investors out of megabucks. If you read any of those stories, they were eye-opening. Shell companies (no employees, no assets, etc.) who set up websites, listed names of executives and biographies (all bogus) with pictures (stolen from various places on the web... totally fictitious), completely fabricated financial reports and information. Many of these companies even had glowing reports written up in local newspapers who were taken for a ride with all the rest. These type of companies were not legitimate companies... but even they filed with the respective state.
Ping to 553. IMO, nothing has been debunked.